Tubular mechanical reactor

Abstract

An apparatus for the direct fluorination of solid particles of polymeric resins capable of being fluorinated in which the solid particles are in contact with the gaseous phase of fluorine/dense carrier fluid in a tubular reactor with an internal mechanical device comprising a rotatable shaft with screw flight, multiblade or wire brush that mechanically fluidizes the solid phase. The design of the internal mechanical device is a function of the diameter and length of the tubular reactor and the reaction time and other physical properties of the solid particles of polymeric resins. The internal mechanical device prevents agglomeration of the solid particles and promotes uniform contact with the gaseous phase by inducing mobility to the solid particles. The enhancement of solid surface contact with the gaseous phase assists the reaction between the solid polymeric resin and the elemental fluorine, as well as the heat dissipation into the dense carrier fluid.

I claim: 
     
       1. An apparatus for fluorinating particulate polymeric materials capable of being fluorinated comprising: a vapour-tight tubular reactor having a rotatable mechanical fluidizer mounted for rotation within a housing, said rotatable mechanical fluidizer having a plurality of openings for allowing a vapour fluid to pass therethrough, said housing having a feed end and a discharge end, means for rotating said rotatable mechanical fluidizer, means for feeding a polymeric material in particulate form to the housing at the feed end thereof for passage through the vapour tight tubular reactor, a closed mixing tank, a source of fluorine and a source of carrier vapour fluid, said closed mixing tank containing a mixture of fluorine and carrier vapour fluid preparatory to feeding a mixture of fluorine and carrier vapour fluid to the vapour tight tubular reactor vessel, said carrier vapour fluid selected from the group consisting of helium, nitrogen, argon, and a dense carrier fluid having a critical temperature higher than ambient temperature, a boiling point lower than ambient temperature minus 60 celcius degrees, and a molecular weight greater than the molecular weight of elemental fluorine, means for feeding said mixture of fluorine and carrier vapour fluid to said tubular vapour-tight reactor at one end of the housing for passage through the plurality of openings in the rotatable mechanical fluidizer to react with the fluidized polymeric material, evacuating pump means in communication with the housing for drawing the fluorine and carrier vapour fluid mixture through the tubular vapour-tight reactor, and means for discharging fluorinated material from the discharge end of the housing. 
     
     
       2. An apparatus as claimed in claim 1 in which the rotatable mechanical fluidizer is a rotatable screw having a continuous helichoid flight or a plurality of sectional flights, a continuous or sectional ribbon flight, or plurality of uniform or variable length radial blades. 
     
     
       3. An apparatus as claimed in claim 2 in which means are provided to pass the fluorine and carrier vapour fluid through the vapour-tight tubular reactor counter-current to the flow of particulate polymeric material. 
     
     
       4. An apparatus as claimed in claim 2 in which means are provided to pass the fluorine and carrier vapour fluid through the vapour-tight tubular reactor co-current to the flow of particulate polymeric material. 
     
     
       5. An apparatus as claimed in claim 2 in which the vapour-tight tubular reactor is oriented at an angle between 0° and 90° with the horizontal. 
     
     
       6. An apparatus as claimed in claim 1 in which the feed end of the housing is higher than the discharge end of the housing, the rotatable mechanical fluidizer is a screw conveyor, and the means for feeding the mixture of fluorine and carrier vapour fluid is located at the discharge end whereby the passage of fluid mixture is counter-current to the passage of particulate polymeric material. 
     
     
       7. An apparatus as claimed in claim 1 in which the feed end of the housing is lower than the discharge end of the housing, the rotatable mechanical fluidizer is a screw conveyor, and the means for feeding the mixture of fluorine and carrier vapour fluid is located at the feed end whereby the passage of fluid is co-current to the passage of particulate polymeric material. 
     
     
       8. An apparatus for fluorinating particulate polymeric materials capable of being fluorinated comprising a rotatable screw with a continuous helichoid flight or sectional flights located within a vapour-tight cylindrical housing, said vapour-tight cylindrical housing having a feed end and a discharge end, means for rotating said rotatable screw, said continuous helichoid flight or sectional flights having a plurality of perforations for allowing a vapour to pass therethrough, means for feeding polymeric material in particulate form to the vapour-tight cylindrical housing at the feed end thereof, a closed mixing tank, a source of fluorine and a source of carrier vapour fluid, said closed mixing tank containing a mixture of fluorine and carrier vapour fluid preparatory to feeding a mixture of fluorine and carrier vapour fluid to the vapour-tight cylindrical housing, said carrier vapour fluid selected from the group consisting of helium, nitrogen, argon, and a dense carrier fluid having a critical temperature higher than ambient temperature, a boiling point lower than ambient temperature minus 60 celcius degrees, and a molecular weight greater than the molecular weight of elemental fluorine, means for feeding said mixture of fluorine and carrier vapour fluid to said vapour-tight cylindrical housing at one end of the vapour-tight cylindrical housing for passing through the plurality of perforations in the screw continuous helichoid flight or sectional flights for reaction with the polymeric material, evacuating pump means in communication with the vapour-tight cylindrical housing for drawing the fluorine and carrier vapour fluid mixture through the vapour-tight cylindrical housing, and means for discharging fluorinated material from the discharge end of the vapour-tight cylindrical housing.